In this wiki, our class will be discussing the topics matter and the periodic table. Just a reminder to everyone that this wiki is due on 11/18. I will be printing it out at 10:00 pm on 11/17. I hope everyone is working on this completes their section in the given time table. As Mr. Desjardin's says, "Don't wait until the last minute." If anyone has any questions about group assignments or anything along those lines, feel free to contact me either on Facebook, Twitter: a_whalen15 or by cell: 401-487-4812. Thanks and good luck everyone!
PROPERTIES OF MATTER
Co-editor: Emily Mills
Team 1: Joe Geraghty
Section 2.1 DESCRIBING MATTER (Emily Mills)
Observing its properties
Properties used to describe matter can be classified as extensive or intensive.
Extensive Properties - a property that depends on the amount of matter in a sample
Matter is anything that has mass and takes up space.
Massof an object is a measure of the amount of matter the object contains.
Volume of an object is a measure of the space occupied by the object.
Intensive Properties - a property that depends on the type of matter in a sample, not the amount of matter
Examples: hardness; softness; material made from
IDENTIFYING SUBSTANCES
Every object has its own chemical makeup or composition.
Substanceis matter that has a uniform and definite composition.
Examples: gold and copper
Every sample of a given substance has identical intensive properties because every sample has the same composition.
Physical Properties are a quality or condition of a substance that can be observed or measured without changing the substance's composition.
Examples: hardness; color; conductivity; and malleability.
Help chemists identify substances.
Physical Properties of Some Substances
Substance State Color Melting Point (°C) Boiling Point (°C)
Neon Gas Colorless -249 -246
Oxygen Gas Colorless -218 -183
Chlorine Gas Greenish-Yellow. -101 -34
Ethanol Liquid Colorless -117 78
Mercury Liquid Silvery-white -39 357
Bromine Liquid Reddish-brown -7 59
Water Liquid Colorless 0 100
Sulfur Solid Yellow 115 445
Sodium chloride
Solid White 801 1413
Gold Solid Yellow 1064 2856
Copper Solid Yellow 1084 2562
STATES OF MATTER ( Joe Geraghty)
Solids-definite shape and volume
Liquids-indefinite shape, flows, yet has a fixed volume
Gases-form of matter that takes both the shape and volume of its container
Vapor-the gaseous state of a substance that is generally a liquid or solid at room temperature
PHYSICAL CHANGE
Some properties of a material change, but the composition of the material does not change
Reversible
Boil, freeze, melt, and condense
Irreversible
Break, split, grind, cut, and crush
Mixtures - explained by group 2
Co-editor: Matt Moschella
Members: Emily Healy
Section 2.2
Classifying mixtures
a mixture is a physical blend of two or more components.
based on the distribution of their components, mixtures can either be classified as heterogenous mixtures or homogenous mixtures.
Heterogenous mixtures
a mixture in which the composition is NOT uniform throughout. Homogenous mixtures
a mixture in which the composition is unifrom throughout.
a solution is another name for a homogenous mixture.
a phase is used to describe any part of a sample with uniform composition and properties.
Separating Mixtures
Separating mixtures can sometimes be challenging
Differences in physical properties can be used to separate mixtures Examples
Filtration Filtration - the process that separates a solid from the liquid in a heterogeneous mixture
Distillation Distillation - the process in which liquid is boiled to produce a vapor that is then condensed into a liquid
during distillation any particles that dissolved in the liquid will be left behind
*dont get confused by the "cold water in"
and "cold water out" sections, cold water is previously put in that section to cool down the steam.
. It is very likely to attract electrons (when it
bonds with any other element, it either attracts shared electrons or forms a negative ion).
Elements and Compounds- explained by group 3 Co-Editor- Alexandra Ortiz Members: Pat Hodge and Andrew Marcotte
Distinguishing Elements and Compounds Pat Hodge page 48-49
-an element is the simplest form of matter
-a compound is a substance containing two or more elements Breaking Down Compounds
You cannot physically break down a compound like you can physically break down a mixture
A chemical change is a change that produces matter with a different composition An example of a chemical change is a glow stick.
electricity
Water --------> Hydrogen + Oxygen Properties of Compunds
Compounds are very different from elements
examples of compounds: Water and Salt
Andrew Marcotte pgs 50-51 Distinguishing Substances and Mixtures
-using general characteristics to distinguish between substances and mixtures
-This chart summarizes the characteristics of elements, substances, and mixtures
Chemical Symbols
-Chemists use chemical symbols to represent elements
-They also use chemical formulas to represent compounds
-first letter of symbol is always capitalized
-based on the Latin names of the of the elements
-below are some alchemy symbols from the 15th century
Alchemy Symbols
Symbols and Formulas... pg 52
- The English name and Latin name of an element is similiar
i.e:
Ca- Calcium
N- Nitrogen
S- Sulfur
Table 2.2 Symbols and Latin Names for Some Elements
ENGLISH NAME
SYMBOL
LATIN NAME
Sodium
Na
Natrium
Potassium
K
Kalium
Antimony
Sb
Stibium
Copper
Cu
Cuprum
Gold
Au
Aurum
Silver
Ag
Argentum
Iron
Fe
Ferrum
Lead
Pb
Plumbum
Tin
Sn
Stannum
Chemical Symbols - they provide a shorthand way to write the chemical formulas of compounds
Subscripts
- chemical formulas are used to indicate the relative proportions of the elements in a compound
ex: The subscript 2 in H20 indicates that there are always 2 parts of hydrogen for each part of oxygen in water
2.4- chemical reactions Pgs. 53-55 Group 4 co-editor:Drew Humphrey
Members: Kelsey Persechini,Drew Humphrey Recognizing chemical Changes
There are many ways to see if a chemical change occurred
the only way to know for sure it was a chemical change is to test the composition of the substance
Conservation of Mass
Mass stays the same in both chemical Reaction and Physical Change
Law of conservation of mass states that mass is neither destroyed or created in a chemical or physical change
When a ice cube that weights 15grams melts you still have 15 grams of water
When wood burns the Ashes may seem lighter but really gas are leaving and making it seem like matter is destroyed
chemical reaction is a process that leads to the transformation of one set of chemical substances to another.[1] Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity.
6.1- Organizing the Elements
Pgs. 155-157 Group 5 c0-editor: Freddy Dwyer Members: Kevin Petterson
Searching for an Organizing Principle: (Kevin Petterson)
Only 13 elements had been discovered by the year 1700
As Chemists began to use the scientific method to search for new elements, the rate of discovery increased
Chemists used the properties of elements to sort them into groups
1829 German chemist J.W. Dobereiner published a classification system in which elements were grouped into triads,
which is a set of three elements with similar properties
Chemists used the properties of elements to sort them into groups
One element in each triad tended to have properties with values that fell midway between those of the other two elements
Not all known elements can be classified as triads
From 1829 to 1869, many different systems of the periodic table were proposed but none of them were accepted.
In 1869, Russian chemist Dmitri Mendeleev published his version of the periodic table
He developed his periodic table while working on a textbook for his students
He arranged the elements in his periodic table in order of increasing atomic
(Freddy Dwyer)
Here is an early version of Mendeleev's periodic table. Notice the question marks between the entries for zinc (Zn) and arsenic (As). Mendeleev left these spaces in his table because he knew that bromine belonged with chlorine and iodine. He predicted what their properties would be based on their locations in the table. The elements between zinc and arsenic were gallium and germanium, which were discovered in 1875 and 1886. There was a close match between the predicted properties and the actual properties of these elements.
THE PERIODIC LAW
The atomic mass of iodine (I) is 126,90. the atomic mass of tellurium (Te) is 127.60. Based on its chemical properties, iodine belongs in a group with bromine and chlorine. So Mendeleev broke his rule and placed tellurium before iodine in his periodic table.He assumed that the atomic masses for these elements were incorrect, but they were not. Iodine has smaller atomic mass than tellurium does. A similar problem occurred with the other pairs of elements.
Mendeleev developed his table before scientists knew about the structure of atoms. He was not aware of the unique number of protons atoms have. THE NUMBER OF PROTONS IS THE ATOMIC NUMBER IN AN ELEMENT. So in the modern periodic table, elements are arranged in order of increasing atomic mass.The periodic table has 7 periods. Period 1 has 2 elements, period 2 has 8 elements, period 4 has 18 elements, period 6 has 32 elements. Each period corresponds to a principal energy level. Elements within the same period share similar properties. PERIODIC LAW: WHEN ELEMENTS ARE ARRANGED IN ORDER OF INCREASING ATOMIC NUMBER, THERE IS A PERIODIC REPETITION OF THEIR PHYSICAL AND CHEMICAL PROPERTIES.
6.1 Organizing the Elements
Group 6
co editor: Sean Doherty
Members: Matt McKeon
Metals, Nonmetals, and Metalloids.
-The periodic table consists of three main groups which are metals, nonmetals, and metalloids.
-Ratio of each group:
Metals:80%
Nonmetals:15%
Metalloids: 5%
Metals -Good conductors of heat and electrical current.
-Clean cut of metal will usually have high luster, or sheen.
-Sheen- A metals ability to reflect light.
-All metals are solids at room temperature.(Exception of mercury)
-Must metals are ductile, or able to be formed into wires.
-Most metals are malleable, or able to be formed into sheets.
Copper(Cu)
Nonmetals
- Gases at room temperature.
-Include the main components of air- nitrogen and oxygen.
-Few nonmetals are solids, such as sulfur and phosphorus.
-Also one nonmetal, bromine, is a dark red liquid.
-Variation among nonmetals makes it difficult to describe one set of general properties that apply to all nonmetals.
-Nonmetals are not metals, as their name implies.
-They tend to have properties that are opposite of those of metals.
-In general, nonmetals are poor conductors of heat and electric current.
-Carbon is an exception to this rule.
-Solid nonmetals tend to be brittle, meaning that they will shatter if hit with a hammer.
Fluorine(F)
Metalloids
- A metalloid generally has properties that are similar to metals and nonmetals.
-Under some conditions a metalloid may behave like a metal.
-Under other conditions, a metalloid may behave like a nonmetal.
-The behavior often can be controlled by changing the conditions.
-For example, Pure Silicon is a poor conductor of electric current, like most nonmetals. But if a small amount of boron is added to the silicon, the mixture is a good conductor of electric
current, like most metals.
Silicon(Si)
In this picture of the periodic table the nonmetals are to the right of the yellow line represtented in the green color. The metalloids are represented in the light grey
color on the left and right of the yellow line.
6.2 Classifying Elements Group 7 co editor: Chris Delude Members: Katie Manis
Chapter 6.2 pages 161-167 The Periodic table displays the symbols and names of the elements, along with information about the structure of their atoms. Periodic Tables vary in all fonts and colors which represent numerous things. Some change color of the element name to distinguish which form of matter (solid, liquid, or gas) the element is at room temperature. Some have different background colors to distinguish groups of elements, such as alkali elements or alkaline earth metals. The Periodic Table categorizes elements by their electrons because electrons play a key role in determining an element’s properties.
Elements can be sorted into these categories based on their electron configuration: · Noble gases · Representative elements · Transition metals · Inner transition metals
Electron Configurations in Groups:
there is a connection between an element's electron configuration and its location on the periodic table.
Elements can be sorted into noble gasses, representative elements, transition metals, or inner transition metals based on their electric configurations.
The Noble Gasses
the noble gasses are the elements in group 8A of the periodic table.
these nonmetals are sometimes called the inert gasses because they rarely take place in a reaction.
The Representative Elements
elements that display a wide range of physical and chemical properties.
some are metals, some are non-metals and some are metalloids.
most of them are solids but some of them are gasses at room temperature and one of them is a liquid. (bromine)
in atoms of representative elements the s and p sublevels of the highest occupied energy level is not filled.
Transition Elements:
transition elements are elements in the B group of the periodic table which provide a connection between the two sets of representative elements.
there are two types of transition elements. they are transition elements and inner transition metals.
Transition metals
group B elements that are usually displayed in the main body of a periodic table.
copper, silver, gold and iron are examples.
in atoms of a transition metal the highest occupied sublevel and nearby sublevel contain electrons.
these elements are characterized by the presence of electrons in orbitals.
Inner transition metals
appear in the main body of the periodic table.
in atoms of an inner transition metal, the highest occupied sublevel and nearby sublevel generally contain electrons.
the inner transition metals are characterized by orbitals that contain electrons.
Blocks of Elements
the periodic table is divided into sections or blocks that correspond to the highest occupied sublevels.
Each period on the periodic table corresponds to a principal energy level.
for transition elements electrons are added to a sublevel with a principal energy level that is one less than the period number.
for the inner transition metals the principal energy level of the sublevel is two less than the period number.
6.3 Periodic Trends
pgs. 170-172
Group 8
Co-editior: Monika Maczuga (second half of 171-172)
Group Members: Michael Clarke (170- first half of 171)
Periodic Trends in Atomic Size v Each element has one more proton and one more electron than the preceding element. v Across a period, the electrons are added to the same principal energy level. v The shielding effect is constant for all elements in a period. v The increasing nuclear charge pulls the electrons in the highest occupied energy level closer to the nucleus and the atomic size decreases. ü Generally, atomic size decreases across a period from left to right.
Ions v An ion is an atom or group of atoms that has a negative or positive charge. v Both positive and negative ions form when electrons are transferred between atoms. v Atoms of metallic elements tend to form ions by losing one or more electrons from their highest occupied energy levels. Example: Sodium v In a sodium ion, the number of electrons (10) is no longer equal to the number of protons (11). Thus the sodium ion has a net positive charge. Protons dominate! v A cation is an ion with a positive charge. v The charge for a cation is written as a number followed by a plus sign. Good to Know: If the charge is 1+, the number 1 is usually omitted from the complete symbol of the ion. Example: Na +. v Nonmetallic elements tend to form ions by gaining one or more electrons. Example: Chlorine v In a chloride ion, the number of electrons (18) is no longer equal to the number of protons (17). Thus the chloride ion has a net negative charge. Electrons dominate! v An ion with a negative charge is called an anion. v The charge for an anion is written as a number followed by a minus sign. Example: Cl-
For an interactive display of how ionic bonds form, please visit:
Group Members: Abby Williams, Kendall Parsons
Abby Williams: pgs. 173-174 Trends in Ionization Energy
ionization energy: energy required to remove an electron from an atom
*First ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period
atomic size increases as atomic number increases
nuclear charge has smaller effect as size of atom increase
Group Trends in Ionization Energy:
Each green dot represents the data for one element. In general, first ionization energy decreases from top
to bottom within a group. As the size of the atom increases, nuclear charge has a smaller effect on the
electrons in the highest occupied energy level. So less energy is required to remove an electron from
this energy level and the first ionization energy is lower.
Electronegativity explained by Group 10 Members: Lindsey Trafford (Co-editor) p177Lauren Rossi p178Nathaniel Gallishaw p177Trends in Electronegativity
Electronegativity - the ability of an atom to attract electrons when the atom is in a compound
it is a property that can be used to predict the type of bond that will form during a reaction
- noble gases do not form many compounds - Linus Pauling was the first to define electronegativity *he won a Noble Prize in Chemistry for his work on
chemical bonds
Electronegativity Trends in the Periodic Table (Nathaniel Gallishaw)
Generally, values for electronegativity decrease when moving from the top to the bottom of a group.
In representative elements, these values increase when moving from the left to the right of a period.
Therefore, metals on the left side of the periodic table have low electronegative values. Nonmetals on the right
side of the periodic table (except for the noble gases) have high electronegative values. There is not a trend in
values for the transition metals.
Cesium's 0.7 value makes it the least electronegative element. It is least likely to attract electrons (when it reacts,
it usually loses electrons and forms positive ions).
Fluorine's 4.0 value means that it is the most electronegative element. It is very likely to attract electrons (when it
bonds with any other element, it either attracts shared electrons or forms a negative ion).
Electronegativity Values for Selected Elements (Nathaniel Gallishaw)
H 2.1
Li 1.0
Be 1.5
B 2.0
C 2.5
N 3.0
O 3.5
F 4.0
Na 0.9
Mg 1.2
Al 1.5
Si 1.8
P 2.1
S 2.5
Cl 3.0
K 0.8
Ca 1.0
Ga 1.6
Ge 1.8
As 2.0
Se 2.4
Br 2.8
Rb 0.8
Sr 1.0
In 1.7
Sn 1.8
Sb 1.9
Te 2.1
I 2.5
Cs 0.7
Ba 0.9
Tl 1.8
Pb 1.9
Bi 1.9
Summary of Trends
Properties such as atomic size, ionization energy, ionic size, and electronegativity vary within groups and across periods
The trends that exist among these properties can be explained by variations in atomic structure.
Editor: Andrew Whalen
In this wiki, our class will be discussing the topics matter and the periodic table. Just a reminder to everyone that this wiki is due on 11/18. I will be printing it out
at 10:00 pm on 11/17. I hope everyone is working on this completes their section in the given time table. As Mr. Desjardin's says, "Don't wait until the last minute."
If anyone has any questions about group assignments or anything along those lines, feel free to contact me either on Facebook, Twitter: a_whalen15 or by
cell: 401-487-4812. Thanks and good luck everyone!
PROPERTIES OF MATTER
Co-editor: Emily Mills
Team 1: Joe Geraghty
Section 2.1
DESCRIBING MATTER (Emily Mills)
IDENTIFYING SUBSTANCES
Physical Properties of Some Substances
Substance State Color Melting Point (°C) Boiling Point (°C)
Neon Gas Colorless -249 -246
Oxygen Gas Colorless -218 -183
Chlorine Gas Greenish-Yellow. -101 -34
Ethanol Liquid Colorless -117 78
Mercury Liquid Silvery-white -39 357
Bromine Liquid Reddish-brown -7 59
Water Liquid Colorless 0 100
Sulfur Solid Yellow 115 445
Sodium chloride
Solid White 801 1413
Gold Solid Yellow 1064 2856
Copper Solid Yellow 1084 2562
STATES OF MATTER ( Joe Geraghty)
PHYSICAL CHANGE
Mixtures - explained by group 2
Co-editor: Matt Moschella
Members: Emily Healy
Section 2.2
Classifying mixtures
a mixture is a physical blend of two or more components.
based on the distribution of their components, mixtures can either be classified as heterogenous mixtures or homogenous mixtures.
Heterogenous mixtures
a mixture in which the composition is NOT uniform throughout.
Homogenous mixtures
a mixture in which the composition is unifrom throughout.
a solution is another name for a homogenous mixture.
a phase is used to describe any part of a sample with uniform composition and properties.
Separating MixturesSeparating mixtures can sometimes be challenging
Differences in physical properties can be used to separate mixtures
Examples
Filtration
Filtration - the process that separates a solid from the liquid in a heterogeneous mixture
Distillation
Distillation - the process in which liquid is boiled to produce a vapor that is then condensed into a liquid
during distillation any particles that dissolved in the liquid will be left behind
*dont get confused by the "cold water in"and "cold water out" sections, cold water is previously put in that section to cool down the steam.
. It is very likely to attract electrons (when it
bonds with any other element, it either attracts shared electrons or forms a negative ion).
Elements and Compounds- explained by group 3
Co-Editor- Alexandra Ortiz
Members: Pat Hodge and Andrew Marcotte
Distinguishing Elements and Compounds Pat Hodge page 48-49
-an element is the simplest form of matter
-a compound is a substance containing two or more elements
Breaking Down Compounds
You cannot physically break down a compound like you can physically break down a mixture
A chemical change is a change that produces matter with a different composition An example of a chemical change is a glow stick.
electricity
Water --------> Hydrogen + Oxygen
Properties of Compunds
Compounds are very different from elements
examples of compounds: Water and Salt
Andrew Marcotte pgs 50-51
Distinguishing Substances and Mixtures
-using general characteristics to distinguish between substances and mixtures
-This chart summarizes the characteristics of elements, substances, and mixtures
Chemical Symbols
-Chemists use chemical symbols to represent elements
-They also use chemical formulas to represent compounds
-first letter of symbol is always capitalized
-based on the Latin names of the of the elements
-below are some alchemy symbols from the 15th century
Symbols and Formulas... pg 52
- The English name and Latin name of an element is similiar
i.e:
Table 2.2 Symbols and Latin Names for Some Elements
Chemical Symbols
- they provide a shorthand way to write the chemical formulas of compounds
Subscripts
- chemical formulas are used to indicate the relative proportions of the elements in a compound
ex: The subscript 2 in H20 indicates that there are always 2 parts of hydrogen for each part of oxygen in water
2.4- chemical reactions
Pgs. 53-55
Group 4
co-editor:Drew Humphrey
Members: Kelsey Persechini,Drew Humphrey
Recognizing chemical Changes
- There are many ways to see if a chemical change occurred
For exampleConservation of Mass
chemical reaction is a process that leads to the transformation of one set of chemical substances to another.[1] Chemical reactions can be either spontaneous, requiring no input of energy, or non-spontaneous, typically following the input of some type of energy, such as heat, light or electricity.
CHEMICAL REACTION:
http://www.youtube.com/watch?v=hVK9Om4wzBM&feature=related
6.1- Organizing the Elements
Pgs. 155-157
Group 5
c0-editor: Freddy Dwyer
Members: Kevin Petterson
Searching for an Organizing Principle: (Kevin Petterson)
- Only 13 elements had been discovered by the year 1700
- As Chemists began to use the scientific method to search for new elements, the rate of discovery increased
- Chemists used the properties of elements to sort them into groups
- 1829 German chemist J.W. Dobereiner published a classification system in which elements were grouped into triads,
which is a set of three elements with similar properties(Freddy Dwyer)
Here is an early version of Mendeleev's periodic table. Notice the question marks between the entries for zinc (Zn) and arsenic (As). Mendeleev left these spaces in his table because he knew that bromine belonged with chlorine and iodine. He predicted what their properties would be based on their locations in the table. The elements between zinc and arsenic were gallium and germanium, which were discovered in 1875 and 1886. There was a close match between the predicted properties and the actual properties of these elements.
THE PERIODIC LAW
The atomic mass of iodine (I) is 126,90. the atomic mass of tellurium (Te) is 127.60. Based on its chemical properties, iodine belongs in a group with bromine and chlorine. So Mendeleev broke his rule and placed tellurium before iodine in his periodic table.He assumed that the atomic masses for these elements were incorrect, but they were not. Iodine has smaller atomic mass than tellurium does. A similar problem occurred with the other pairs of elements.
Mendeleev developed his table before scientists knew about the structure of atoms. He was not aware of the unique number of protons atoms have. THE NUMBER OF PROTONS IS THE ATOMIC NUMBER IN AN ELEMENT. So in the modern periodic table, elements are arranged in order of increasing atomic mass.The periodic table has 7 periods. Period 1 has 2 elements, period 2 has 8 elements, period 4 has 18 elements, period 6 has 32 elements. Each period corresponds to a principal energy level. Elements within the same period share similar properties. PERIODIC LAW: WHEN ELEMENTS ARE ARRANGED IN ORDER OF INCREASING ATOMIC NUMBER, THERE IS A PERIODIC REPETITION OF THEIR PHYSICAL AND CHEMICAL PROPERTIES.
6.1 Organizing the Elements
Group 6
co editor: Sean Doherty
Members: Matt McKeon
Metals, Nonmetals, and Metalloids.
-The periodic table consists of three main groups which are metals, nonmetals, and metalloids.
-Ratio of each group:
Metals:80%
Nonmetals:15%
Metalloids: 5%
Metals
-Good conductors of heat and electrical current.
-Clean cut of metal will usually have high luster, or sheen.
-Sheen- A metals ability to reflect light.
-All metals are solids at room temperature.(Exception of mercury)
-Must metals are ductile, or able to be formed into wires.
-Most metals are malleable, or able to be formed into sheets.
Copper(Cu)
Nonmetals
- Gases at room temperature.
-Include the main components of air- nitrogen and oxygen.
-Few nonmetals are solids, such as sulfur and phosphorus.
-Also one nonmetal, bromine, is a dark red liquid.
-Variation among nonmetals makes it difficult to describe one set of general properties that apply to all nonmetals.
-Nonmetals are not metals, as their name implies.
-They tend to have properties that are opposite of those of metals.
-In general, nonmetals are poor conductors of heat and electric current.
-Carbon is an exception to this rule.
-Solid nonmetals tend to be brittle, meaning that they will shatter if hit with a hammer.
Fluorine(F)
Metalloids
- A metalloid generally has properties that are similar to metals and nonmetals.
-Under some conditions a metalloid may behave like a metal.
-Under other conditions, a metalloid may behave like a nonmetal.
-The behavior often can be controlled by changing the conditions.
-For example, Pure Silicon is a poor conductor of electric current, like most nonmetals. But if a small amount of boron is added to the silicon, the mixture is a good conductor of electric
current, like most metals.
Silicon(Si)
In this picture of the periodic table the nonmetals are to the right of the yellow line represtented in the green color. The metalloids are represented in the light grey
color on the left and right of the yellow line.
6.2 Classifying Elements
Group 7
co editor: Chris Delude
Members: Katie Manis
Chapter 6.2 pages 161-167
The Periodic table displays the symbols and names of the elements, along with information about the structure of their atoms. Periodic Tables vary in all fonts and colors which represent numerous things. Some change color of the element name to distinguish which form of matter (solid, liquid, or gas) the element is at room temperature. Some have different background colors to distinguish groups of elements, such as alkali elements or alkaline earth metals. The Periodic Table categorizes elements by their electrons because electrons play a key role in determining an element’s properties.
Elements can be sorted into these categories based on their electron configuration:
· Noble gases
· Representative elements
· Transition metals
· Inner transition metals
Electron Configurations in Groups:
The Noble Gasses
The Representative Elements
Transition Elements:
Transition metals
Inner transition metals
Blocks of Elements
- the periodic table is divided into sections or blocks that correspond to the highest occupied sublevels.
- Each period on the periodic table corresponds to a principal energy level.
- for transition elements electrons are added to a sublevel with a principal energy level that is one less than the period number.
- for the inner transition metals the principal energy level of the sublevel is two less than the period number.
**Click here for an interactive periodic table experience**Chapter 6: Lesson 3 Periodic Trends
Pgs. 170 - 178
6.3 Periodic Trends
pgs. 170-172
Group 8
Co-editior: Monika Maczuga (second half of 171-172)
Group Members: Michael Clarke (170- first half of 171)
Periodic Trends in Atomic Size
v Each element has one more proton and one more electron than the preceding element.
v Across a period, the electrons are added to the same principal energy level.
v The shielding effect is constant for all elements in a period.
v The increasing nuclear charge pulls the electrons in the highest occupied energy level closer to the nucleus and the atomic size decreases.
ü Generally, atomic size decreases across a period from left to right.
Ions
v An ion is an atom or group of atoms that has a negative or positive charge.
v Both positive and negative ions form when electrons are transferred between atoms.
v Atoms of metallic elements tend to form ions by losing one or more electrons from their highest occupied energy levels.
Example: Sodium
v In a sodium ion, the number of electrons (10) is no longer equal to the number of protons (11). Thus the sodium ion has a net positive charge. Protons dominate!
v A cation is an ion with a positive charge.
v The charge for a cation is written as a number followed by a plus sign.
Good to Know: If the charge is 1+, the number 1 is usually omitted from the complete symbol of the ion.
Example: Na +.
v Nonmetallic elements tend to form ions by gaining one or more electrons.
Example: Chlorine
v In a chloride ion, the number of electrons (18) is no longer equal to the number of protons (17). Thus the chloride ion has a net negative charge. Electrons dominate!
v An ion with a negative charge is called an anion.
v The charge for an anion is written as a number followed by a minus sign.
Example: Cl-
For an interactive display of how ionic bonds form, please visit:
http://www.teachersdomain.org/resource/lsps07.sci.phys.matter.ionicbonding/
In this game, you are challenged to create several compounds using ions:
http://www.learner.org/interactives/periodic/groups_interactive.html
In love with ions? In this activity, you are challenged to transform elements into their appropriate ions:
http://www.media.pearson.com.au/schools/cw/au_sch_jeffery_cd1_1/int/ch5/ionElectronConfigs/IonElectronConfigs.html
6.3 Periodic Trends
pgs. 173-174
Co-editior: Sejal Batra
Group Members: Abby Williams, Kendall Parsons
Abby Williams: pgs. 173-174
Trends in Ionization Energy
ionization energy: energy required to remove an electron from an atom
*First ionization energy tends to decrease from top to bottom within a group and increase from left to right across a period
Group Trends in Ionization Energy:
Each green dot represents the data for one element. In general, first ionization energy decreases from top
to bottom within a group. As the size of the atom increases, nuclear charge has a smaller effect on the
electrons in the highest occupied energy level. So less energy is required to remove an electron from
this energy level and the first ionization energy is lower.
Electronegativity explained by Group 10
Members: Lindsey Trafford (Co-editor) p177Lauren Rossi p178Nathaniel Gallishaw p177Trends in Electronegativity
- Electronegativity - the ability of an atom to attract electrons when the atom is in a compound
- it is a property that can be used to predict the type of bond that will form during a reaction
- noble gases do not form many compounds- Linus Pauling was the first to define electronegativity
*he won a Noble Prize in Chemistry for his work on
chemical bonds
Electronegativity Trends in the Periodic Table (Nathaniel Gallishaw)
Generally, values for electronegativity decrease when moving from the top to the bottom of a group.
In representative elements, these values increase when moving from the left to the right of a period.
Therefore, metals on the left side of the periodic table have low electronegative values. Nonmetals on the right
side of the periodic table (except for the noble gases) have high electronegative values. There is not a trend in
values for the transition metals.
Cesium's 0.7 value makes it the least electronegative element. It is least likely to attract electrons (when it reacts,
it usually loses electrons and forms positive ions).
Fluorine's 4.0 value means that it is the most electronegative element. It is very likely to attract electrons (when it
bonds with any other element, it either attracts shared electrons or forms a negative ion).
Electronegativity Values for Selected Elements (Nathaniel Gallishaw)
Summary of Trends
Properties such as atomic size, ionization energy, ionic size, and electronegativity vary within groups and across periodsThe trends that exist among these properties can be explained by variations in atomic structure.